A typical heat exchanger comprises of a generally straight tubular section having a generally smooth exterior surface with a secondary extended surface comprising generally of fin structures coupled to the exterior surface of the tubular section. The tubular section may be round or rectangular in shape. The fin structure may be smooth, or may feature surface enhancements, such as louvers or dimples, for example. The typical heat exchanger design, generally called compact heat exchangers, pack as much surface area in a given package space, without necessarily being concerned with extracting as much performance out of a given surface area. Due to this design methodology, performance yield out of any given surface area is limited. However, the design compensates for low performance over a given surface area by packaging as much surface area in a given space. For example, wherein the primary surface area with the highest heat transfer performance, comprising of a generally tubular structure transporting heat exchange medium within may be limited, far more significant amount of secondary surface area is obtained by attaching extended surfaces on the primary surface. The extended secondary surfaces typically used in the art is usually in the form of fins. This design significantly increases the amount of surface area available to facilitate heat transfer, in a magnitude of a few times over the primary surface area, such as 2 times or more, for example. In such an arrangement, the primary surface area generally performs at the highest rate of heat transfer efficiency, while the extended surface area performs at a diminished capacity. Therefore, when considered as a package, the heat exchanger of such a design suffers from rather modest heat transfer performance, indicated by a low overall heat transfer coefficient, for example. Also, with the addition of fin structures, the heat exchanger may have to be made physically larger as a package or weigh more due to the addition of significant amount of fin material. Additionally, the parts count may significantly increase, while complicating the manufacturing procedure, due to the addition of fin structures, thus by extension, generally making the manufacturing process costly and complicated. Fin structures generally need to be fabricated out of an extremely thin material to function at an optimal performance level, making the structure prone to damage. Furthermore, applying significant amount of fin material to increase the heat transfer surface may in turn negatively impact the flow of heat transfer medium through such an arrangement, increasing the pressure drop of the heat exchange medium, further hampering the overall performance of the heat exchanger.
A tube and chamber heat exchanger with a medium directing insert takes a different approach to improving the heat transfer performance, by extracting as much performance out of any given surface area, while eliminating as much surface area of a heat exchanger that would not extract high level of heat transfer. Secondary surfaces in the form of fins are generally eliminated, while primary surface area extracting the highest level of heat transfer is maximized. Additionally, the heat transfer performance of a primary surface of the tube and chamber heat exchanger is enhanced by utilizing a heat exchange medium transporting technique that induces swirling and mixing effect to the heat transfer medium flowing within the heat exchanger, known in the art to enhance heat transfer efficiency, further enhancing the overall heat transfer performance. As a result, a heat exchanger of this kind performs at a very high efficiency level, indicated by a higher overall heat transfer coefficient throughout its surface area, lending to a smaller heat exchanger package, compared to a conventional heat exchanger design known in the art. A smaller heat exchanger package lends itself to further benefits, such as lighter weight, less material usage, and low cost. Reduced parts count as a result lends itself to an easier manufacturing process. A typical tube and chamber heat exchanger is characterized by having a distinct tube section, a chamber section, and a medium directing insert disposed within the chamber section.
The present invention is an improved tube and chamber heat exchanger utilizing an enhanced medium directing insert design yielding higher heat transfer performance, while simplifying the manufacturing process. Furthermore, the present invention features improvements to the medium flow pattern within the chamber section, which lends itself to reduction of pressure drop of heat exchange medium flowing inside the chamber section, an advantageous feature in a typical heat exchanger application. The present invention accomplishes all the benefits mentioned herein while retaining all the heat transfer characteristics of a tube and chamber heat exchanger, while simplifying the manufacturing process of assembling a heat exchanger comprising of the present invention.